The IA-64 System Architecture - DIG64
The IA-64 System Architecture - DIG64
The IA-64 System Architecture - DIG64
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Parallelism Across <strong>System</strong> Calls<br />
Application<br />
Address<br />
Space<br />
Application Code<br />
…<br />
// make system call<br />
br.call _write<br />
...<br />
EPC Page (PL promote and execute only)<br />
_write:<br />
….<br />
epc // privilege promote<br />
// without pipeline flush<br />
br os_write<br />
….<br />
Operating<br />
<strong>System</strong><br />
Kernel<br />
(privileged code)<br />
os_write:<br />
…<br />
// perform system call<br />
br.ret // demote PL and return<br />
to user<br />
Fast <strong>System</strong> Calls Improve Synergy<br />
Between OS & Application<br />
®
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